/*** $Id: lmem.c,v 1.70 2005/12/26 13:35:47 roberto Exp $** Interface to Memory Manager** See Copyright Notice in lua.h*/#include <stddef.h>#define lmem_c#define LUA_CORE#include "lua.h"#include "ldebug.h"#include "ldo.h"#include "lmem.h"#include "lobject.h"#include "lstate.h"/*** About the realloc function:** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize);** (`osize' is the old size, `nsize' is the new size)**** Lua ensures that (ptr == NULL) iff (osize == 0).**** * frealloc(ud, NULL, 0, x) creates a new block of size `x'**** * frealloc(ud, p, x, 0) frees the block `p'** (in this specific case, frealloc must return NULL).** particularly, frealloc(ud, NULL, 0, 0) does nothing** (which is equivalent to free(NULL) in ANSI C)**** frealloc returns NULL if it cannot create or reallocate the area** (any reallocation to an equal or smaller size cannot fail!)*/#define MINSIZEARRAY	4void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems,                     int limit, const char *errormsg) {  void *newblock;  int newsize;  if (*size >= limit/2) {  /* cannot double it? */    if (*size >= limit)  /* cannot grow even a little? */      luaG_runerror(L, errormsg);    newsize = limit;  /* still have at least one free place */  }  else {    newsize = (*size)*2;    if (newsize < MINSIZEARRAY)      newsize = MINSIZEARRAY;  /* minimum size */  }  newblock = luaM_reallocv(L, block, *size, newsize, size_elems);  *size = newsize;  /* update only when everything else is OK */  return newblock;}void *luaM_toobig (lua_State *L) {  luaG_runerror(L, "memory allocation error: block too big");  return NULL;  /* to avoid warnings */}/*** generic allocation routine.*/void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {  global_State *g = G(L);  lua_assert((osize == 0) == (block == NULL));  block = (*g->frealloc)(g->ud, block, osize, nsize);  if (block == NULL && nsize > 0)    luaD_throw(L, LUA_ERRMEM);  lua_assert((nsize == 0) == (block == NULL));  g->totalbytes = (g->totalbytes - osize) + nsize;  return block;}